Land vehicles – Body elevation or tilt – Loading position
Reexamination Certificate
1999-10-20
2001-08-14
Mai, Lanna (Department: 3619)
Land vehicles
Body elevation or tilt
Loading position
C280S006155, C280S043110, C280S043140, C280S043180, C280S043200, C280S656000, C280S791000, C280S789000
Reexamination Certificate
active
06273435
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to a trailer which is especially useful in lifting and transporting pieces of equipment. The present invention is an improvement over a prior art trailer sold by bil-jax, Inc. of Archbold, Ohio including the Escalate Trailer Workforce® models ET 1500 and ET 2000. The prior art trailer is designed allow a piece of equipment to be transported from one place to another by being hitched to a vehicle. The prior art trailer has a bed which is lowered to the ground using a winch operation such that the bed does not tilt when being raised or lowered. When using the prior art trailer, a piece of equipment is positioned or moved onto the lowered bed. The bed is then raised by a winch into an elevated position so that the bed clears the ground. Operation of this prior art trailer included the raising or lowering by using a hand or automatic winch and cable which pulled the bed into a raised position. The prior art trailer required a great amount of power to raise the bed and the equipment thereon to the raised position. Accordingly, the person operating the trailer must exert extreme amount of effort to raise or lower the trailer.
The prior art trailer also was held in position by a standard type of toggle retaining latch to secure the bed to the frame once the bed was in the raised position. It is very important that the bed be very securely held in the raised position such that the equipment being hauled or transported is not damaged and that no injury occurs to the trailer operator. Such equipment often includes heavy and expensive equipment such as personnel lifts, trenchers, compactors, generators, appliances, tillers, welding equipment, lawn mowers, and the like. These pieces of equipment must be able to be securely held on the bed and not inadvertently become detached when the trailer is in use.
The primary object of the present invention is to provide an improved trailer where a bed can be raised and lowered in a non-tilting manner and can be used to transport heavy pieces of equipment. The trailer of the present invention includes a lifting mechanism and a passive locking mechanism which provide the operator with a great mechanical advantage thus reducing the amount of force required to raise and lower the bed.
In addition, the lifting mechanism and the locking mechanism together provide a trailer system having safety and energy conserving features.
SUMMARY OF THE INVENTION
The present invention is a trailer that can be operated by one person to move heavy and awkward loads or equipment and to transport or tow the load or equipment behind a vehicle.
The improved trailer of the present invention has a frame and at least one wheel and axle assembly on opposing sides of the frame. The wheel and axle assemblies allow the trailer to be readily moved from one location to a different location. The trailer also has a hitching mechanism so that the trailer can be towed by a suitable vehicle.
The trailer also has a moveable bed operatively attached to the frame. The bed has a bottom surface or deck and opposing sides which extend in a vertical direction from the deck. The sides of the moveable bed include at least one, and preferably a plurality of, cam follower tracks which extend at an angle from the deck to a top railing. The cam follower tracks matingly engage opposing cams mounted on the frame. The moveable bed is operatively connected to a lifting mechanism which raises and lowers the bed in a non-tilting manner. In a preferred embodiment, the lifting mechanism is operatively connected such that there is approximately a 2 to 1 mechanical disadvantage which advantageously harnesses the power potential of the lifting mechanism. The lifting mechanism which utilizes a small stroke and can be of a small size and still have sufficient power to raise and lower heavy loads.
The lifting mechanism is attached to the bed with a lever and a connecting bar. The connecting bar is pivotally attached at a first end to the bed and pivotally attached at a second end to a first end of the lever. The lever is pivotally connected at a midpoint to the lifting mechanism. The connecting bar attaches the lever to the bed in such a manner that the greatest force is exerted at the beginning of the lift, rather than at the end or midpoint of the lift. This feature reduces the risk of overloading the trailer. According to the present invention, it is not reasonably possible to partially raise any loads in excess of the rating of the lifting mechanism since the greatest force is exerted at the beginning of the lift.
The improved trailer of the present invention also includes a passive securing mechanism which is designed to lock the bed in place when the bed is in a fully raised position. The securing mechanism has a camming latch mechanism which engages a portion of the frame. The securing mechanism is held in place with a restraining mechanism, such as a spring, when the securing mechanism is in a latched position, thus reducing the risk of the securing mechanism becoming unlatched without an outside force being applied to the securing mechanism. When the bed is in a raised position, the bed is resting on level portions of cam follower tracks of the bed. The operator applies a force on the securing mechanism to release the securing mechanism from the bed. The bed is pushed back into angled portions of the cam follower tracks, thereby allowing gravity to lower the bed. The securing mechanism gives the operator a mechanical advantage, thus reducing the force required to lower the bed.
During operation of the trailer, a bed is lowered to the ground in a non-tilting manner and the load or equipment is easily positioned on the bed. The bed is raised in a non-titling manner to an elevated position so that the trailer can be attached to any suitable vehicle for towing.
The improved trailer of the present invention thereby provides a lifting and securing system which has additional safety and energy conserving features. One safety feature is a two-handed requirement in order to lower the bed. One hand of the operator is on the securing mechanism while the other hand is operating a power switch. Another safety feature is that the bed is triplely secured when in a raised position by, first, having the level portions of the cam follower tracks hold the bed in an engaged position; second, the over-center securing mechanism holds the bed in a locked position on the frame; and, third, the lifting mechanism is in a “bottomed out” or fully engaged position such that the lifting mechanism can not move any further, thereby holding the bed in a raised position.
Still another safety feature is the lifting mechanism which is operated in a unidirectional manner such that the lifting mechanism is only powered in one position; i.e., when raising the bed. The unidirectional power safety feature eliminates the risk of the operator powering down the bed without unlatching the securing mechanism, thus preventing any damage to the securing mechanism and/or the operator.
The main energy conserving feature is the unidirectional lifting mechanism which uses power in the up position, while allowing gravity to lower the bed. In a preferred embodiment, the lifting mechanism has a flow restrictor type device on a hydraulic cylinder to control the downward speed of the bed. The unidirectional lifting mechanism uses approximately one-half of the total energy of a power up/power down hydraulic cylinder.
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patent: 4
Bil-Jax, Inc.
Emch, Schaffer, Schaub & Porcello & Co., L.P.A.
Mai Lanna
To Toan C
LandOfFree
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